The rearing behavior of mothers diagnosed (SADS) a depressed and mothers without RDC diagnoses and the behavior of their young children is investigated. Mothers and their 2- and 5-year-olds are observed for 3 half-days in a home-like laboratory apartment in which naturally occurring rearing demands and interactions are experienced, and into which experimental conditions are also introduced. Behavior is measured in terms of cognitive content, affect, communication, and interaction. Direct observations are supplemented by interview data. Psychiatric assessments are made of each child, independent of the observational data. Followup measurements are made over a 2 to 3 year period. The transmission of patterns of behavior and the interaction of biological and environmental variables are the focus of the study. Biological assessment procedures will be introduced at the time of follow-up.